1. Field of the Invention
The present invention relates to a one-way clutch device which functions as a one-way clutch depending upon an input rotational speed, and to a motorcycle using the same.
2. Description of the Background Art
A one-way clutch device is known as described, for example, in Japanese Patent Laid-Open No. Sho 60 (1985)-27854. More specifically, in a state where a rotational speed of an input side rotating member is low, even if the input side rotating member and an output side rotating member relatively rotate in any direction, the members run idle. Meanwhile, in a state where the input side rotating member rotates at a rotational speed above a predetermined rotational speed, if the input side rotating member and the output side rotating member relatively rotate in a specific direction, the members are connected to each other, and the rotary power is transmitted from the input side rotating member to the output side rotating member. If the above-described members relatively rotate in a direction opposite to that described above, the members run idle.
The device described above has such a basic configuration as that in a one-way clutch device 144 shown in FIG. 8 of the present drawings, in which a plurality of rollers 186 are housed between an input coupling 144b and an outer race 144a, and the rotary power can be transmitted from the input coupling 144b to the outer race 144a through the respective rollers 186. The respective rollers 186 are energized by springs 194 through plates 194a toward a direction moving away from positions where the springs allow a connection between the input coupling 144b and the outer race 144a. 
Meanwhile, between the input coupling 144b and the outer race 144a, auxiliary rollers 187 are provided that correspond to the respective rollers 186. The auxiliary rollers 187 are supported by oblong holes 187a, respectively, which are formed in a sidewall of the input coupling 144b. Each of the auxiliary rollers 187 can be moved along the oblong hole 187a by centrifugal force when the input coupling 144b rotates. Depending upon a rotational speed of the input coupling 144b, the respective auxiliary rollers 187 move the corresponding rollers 186 against elastic force of the springs 194. Thus, the respective rollers 186 are moved to positions where the rollers 186 allow a connection between the input coupling 144b and the outer race 144a. Consequently, the one-way clutch device 144 functions as a one-way clutch. The one-way clutch device 144 as described above can be provided between the engine and the torque converter of a vehicle.
However, in the one-way clutch device as described above, since the auxiliary roller is moved along the oblong hole formed in the sidewall of the input coupling, based on long-term use, a configuration is needed so as to smoothly move the auxiliary roller without causing the auxiliary roller to fall out of the oblong hole. This complicates the configuration of the one-way clutch device. Thus, an improvement in this regard is needed.
At the same time, to improve the handleability of a motorcycle when an engine is stopped or idled it has been considered to employ the one-way clutch device as described above in the motorcycle.